ALAN ALDA There's a story that goes like this. Sometime in the
late 1500s, Galileo Galilei left his house just down the street
here in Pisa, and headed for the tower.

ALAN ALDA (NARRATION) He had a novel idea. And the leaning tower
- yes, even then it was leaning- was just what he needed.

ALAN ALDA Four hundred years ago, the conventional wisdom about
how the world works hadn't changed since the ancient Greeks.
They said a heavy object falls faster than a lighter one.
Galileo's novel idea was to actually drop two objects and
see which one landed first. In other words, to do an experiment.
He was also probably the first one to say, don't do this at
home. Here goes.

ALAN ALDA (NARRATION) The difference in air resistance between
the two balls means they don't quite land together. But for
Galileo they were close enough to suggest that all objects
fall at the same rate.

ALAN ALDA Now there are spoilsports who say Galileo never did drop
the balls from this tower or any other tower. But the story
has come to symbolize the birth of experimental science: ask
a question, do an experiment, try to figure out why you saw
what you saw. For 400 years now, experimental science has
changed the world. And with any luck, it may help save the
tower where it all began.

ALAN ALDA (NARRATION) One of the world's greatest tourist attractions,
the tower has actually been closed to tourists since 1989.
Its lean had become so alarming that a commission was appointed
to save it. The Commission's man on the spot is Paolo Heiniger.

ALAN ALDA When did the tower start to lean?

PAOLO
HEINIGER Well, actually it started to lean from the beginning,
even during construction.

ALAN ALDA When did they start construction?

PAOLO
HEINIGER They started construction in 1173, and the story
of the construction is a funny one, in the sense that it did
not proceed regularly from the beginning.

ALAN ALDA What, they built it for a while and then stopped?

PAOLO
HEINIGER Yes, the first stage of the construction was performed
from 1173 to 1178, and let's say the construction was stopped
more for political reasons.

ALAN ALDA They had like a strike?

PAOLO
HEINIGER I do not have precise information about it..

ALAN ALDA They didn't have airlines then so they had to strike
the tower.

PAOLO
HEINIGER Maybe it was a matter of money as well.

ALAN ALDA (NARRATION) When work stopped in 1178, the tower was
about half built. A century passed before work began again
and the main tower was completed. This was when the leaning
began, as the tower's weight compressed the clay beneath it
more on the south side than north. Another century passed
before the bell chamber was added. With the tilt now two degrees,
the bell chamber was set at an angle to compensate. Since
then the tower has continued tilting, and today the top is
15 feet. out of the vertical. To stop things getting worse,
600 tons of lead ingots were recently put on the north side
to squash it down a little. It's ugly - but it's working.

ALAN ALDA Have you actually brought it back?

PAOLO
HEINIGER Yes. The tower was, let's say... this 600 ton weight
has caused the horizontal movement of the top of the tower
of about 20mm, almost an inch.

ALAN ALDA Almost an inch...

PAOLO
HEINIGER At the top.

ALAN ALDA Now, it's leaning that way maybe 15, 16 feet and you've
brought it back an inch?

PAOLO
HEINIGER Yes, correct, it is a very small..

ALAN ALDA If I was standing at the top, I don't know if I'd notice
that!

ALAN ALDA (NARRATION) At the bottom, the 10 degree tilt makes just
entering the tower alarming.

ALAN ALDA It's already tilting this way, I'm already falling over.
This is amazing. I mean your tendency is to want to follow
the building. What's all this in here?

PAOLO
HEINIGER Here you can see some of the instrumentation....

ALAN ALDA (NARRATION) The tower is bristling with scientific instruments
to measure even the tiniest movement.

ALAN ALDA There's something that goes up that tube? What is that?

PAOLO
HEINIGER Correct, that is a pendulum..

ALAN ALDA (NARRATION) The pendulum is the instrument that really
counts, because this is what measures the tower's tilt. Hanging
from a beam near the top of the tower, it's hidden in what
looks like a plastic drainpipe.

ALAN ALDA What's this thing over here on this wall, this box on
the wall?

PAOLO
HEINIGER These are strain gauges....

ALAN ALDA (NARRATION) The strain gauges sense stress in the walls.

ALAN ALDA Sorry, I didn't mean to lean on the wall. Pardon me.

PAOLO
HEINIGER This is the dangerous side.

ALAN ALDA I know, I know..

ALAN ALDA (NARRATION) This strain gauge is measuring a several
hundred year old crack. It's on the southern wall - the one
stressed most by the lean - and also the side most affected
by the seasons. In summer, the sun's warmth expands the stones
on the south, pushing the whole tower a little slightly more
upright. So it's the winters that are dangerous.

PAOLO
HEINIGER When it freezes, when it freezes, it means that the
tower kind of freezing, the stones there on the southern side
- which is the dangerous side - decrease in volume, so it
tilts even more.

ALAN ALDA It tilts more. So what's a good day to go up?

PAOLO
HEINIGER Uh, 15th July, mid-day.

ALAN ALDA Today's a good day? Are you sure? How would I know today's
good day? Do you have an instrument in here that will me tell
me today's ...

PAOLO
HEINIGER You must trust me. We go up and then we see what
happens.

ALAN ALDA (NARRATION) What could happen almost at any moment is
that the tower literally explodes. Stress at the level of
the first balcony threatens to burst the stones outwards,
collapsing the entire tower in seconds

ALAN ALDA O.K, I'm set. Andiamo.

PAOLO
HEINIGER Andiamo.

ALAN ALDA (NARRATION) Of course, it was to the likely explosion
point that Paolo wanted to take me. Adding to the excitement,
the balcony has no railing.

ALAN ALDA I'd like to hook on now. Pardon me, where do we hook
on - here?

PAOLO
HEINIGER Yes, here to this rope here.

ALAN ALDA Like that?

PAOLO
HEINIGER Now we can walk safely this way...

ALAN ALDA (NARRATION) These steel bands wrapped right around the
tower - five pairs of them in all - are another temporary
fix, meant to hold the stones in like a corset.

PAOLO
HEINIGER They are embracing actually the external wall of
the structure, and they are meant to contain the risk of local
explosion of material.

ALAN ALDA That's nice. So glad to hear that. Embracing the structure
so it doesn't explode.

PAOLO
HEINIGER Yes.

ALAN ALDA (NARRATION) Of course the source of the tower's problems
isn't up here, its underneath it, where the south side has
sunk more then the north. So experiments are underway to find
a way to sink the north side more to even things up. One idea
being tested is to drill out some of the sand from under the
tower. Another idea involves giant electrodes. In clay, water
molecules have a small positive charge, so would be sucked
out, allowing the clay to compress. Either plan would also
employ anchors sunk deep beneath the tower, tugging down on
the northern side. But whatever plan is employed, it won't
take out so much lean that it's no longer the Leaning Tower.

ALAN ALDA The tower will never be straight up and down.

PAOLO
HEINIGER No, it cannot be straight up and down.

ALAN ALDA Is that because you can't do it, or it won't be such
a good tourist attraction?

PAOLO
HEINIGER Basically, it is because it had been built like a
big banana...

ALAN ALDA Right, I noticed that.

PAOLO
HEINIGER So, if you try to bring it up to a vertical position,
it would probably fall over..

ALAN ALDA The other way!

ALAN ALDA (NARRATION) In fact, the goal is to tilt the top of the
tower back no more than about 3 of the 15 feet it's leaning
now. That way the Leaning Tower should be able to lean safely
for perhaps another 800 years.

ALAN ALDA (NARRATION) From Pisa, we headed south and east, into
the rural backbone of Italy -- the Abruzzo. Snuggled into
the wilderness of the Apennine mountains are little country
towns and villages where I felt right at home.

ALAN ALDA (ON-CAMERA) My ancestors came from this region. In fact,
the name I was born with is Alfonso D'Abruzzo, which means
Alfonse from Abruzzo. They probably came from a little village
just like this. Around the turn of the century many thousands
of people left the Abruzzo region to go to America for the
prosperity that was there. And since then a lot of modern
roads have been built linking Abruzzo with the rest of Italy,
bringing prosperity here, but in the process threatening the
existence of some of the region's oldest inhabitants.

ALAN ALDA (NARRATION) This is Loretta, a very rare and very hungry
brown bear cub.

ALAN ALDA Loretta, va bene Loretta.

ALAN ALDA (NARRATION) It was a surprise to me that Italy even has
any native bears - and in fact the Abruzzo National Park is
one of the last refuges of bears in the whole of Europe. Lorretta
herself was found abandoned.

ALAN ALDA Why would the mother abandon a little cub like this?

FRANCO
TASSI I think that in some years it's not possible that every
mother bear may feed with success two or three bears. In this
case she had two and the strongest was okay but this one needed
help. In nature without our intervention she was lost.

FRANCO
TASSI Ahhh, how good.

ALAN ALDA (NARRATION) Park director Franco Tassi's goal is to bring
the bear back from near certain extinction.

ALAN ALDA Keep it on the stick, kid. As you get more and more of
these bears out in the mountains what's the reaction of the
people living around here? Are the bears a danger to the people
coming into town and that kind of thing.

FRANCO
TASSI No, they are very shy. They are very peaceful.

ALAN ALDA She sounded kind of aggressive when she came over.

FRANCO
TASSI Yes, but she's a wild animal. She doesn't like to have
people. She does like honey but not people. And that's the
reason she survives.

ALAN ALDA (NARRATION) Lorretta's ancestors roamed all of Europe.
But thousands of years of climate change and persecution by
man has driven them into a few isolated pockets. One big question
is just how many are left - a question the bear's very sensible
shyness makes it hard to answer. In the Abruzzo, remote video
cameras keep a discreet eye on the bears' favorite haunts,
allowing researchers back at park headquarters to conduct
a bear census. The count continues even during the night -
and reveals a total population of only 80 animals - a number
that puts them on the edge of a genetic precipice.

GIORGIO
BOSCAGLI Having a population lower than 70 or 80 bears means
that the genetic heritage/health of these animals is extremely
reduced. And if you go below that number the probability of
building or even retaining a healthy population in the future
is very slim.

ALAN ALDA (NARRATION) The problem is in-breeding - and one obvious
way to solve it is to bring in some bears from one of the
other remaining European populations. But that poses its own
dilemma - which is why Giorgio Boscagli is setting this snare.
The alarm will bring researchers within minutes, day or night.
After a month of waiting.... The bear is unharmed but angry.
It's tranquilized, then a blood sample taken. A DNA fingerprint
made from the blood reveals the dilemma the researchers are
in. The Abruzzo bear has become genetically distinct from
its European cousins. Long isolated from them, it has evolved
into a unique subspecies. To breed it with other bears would
destroy its uniqueness.

GIORGIO
BOSCAGLI The Abruzzo brown bear has an evolutionary story
completely different than other European bears. And to lose
that genetic purity, that specialness would be a huge loss.

ALAN ALDA (NARRATION) So the Abruzzo bears will have to make it
on their own. Which is where little Loretta comes in.

ALAN ALDA What will be her future?

FRANCO
TASSI I suppose that it will be very difficult to leave her
in the wild again because she needs the education from the
mother. But we can use this bear to build up a breeding pair
to have more Abruzzo brown bears in the future, like a genetic
bank.

ALAN ALDA (NARRATION) And here's her future mate, Sandrino, an
adult male injured by poachers and brought here to the park.
The hope is that in a few years these two will start parenting
a new generation. Today, Sandrino is due for a pre-marital
blood test, to see if he and Loretta are too closely related..
But first, he must be tranquilized.

ALAN ALDA He looks like he's getting a little drowsy now, a little
sleepy. There he goes, there he goes.

ALAN ALDA (NARRATION) As with the wild bear, a DNA fingerprint
will be run from Sandrino's blood.

ALAN ALDA Where's he taking the blood from?

GIORGIO
BOSCAGLI The jugular.

ALAN ALDA After he gives all that blood do you give him a cup of
coffee and a doughnut?

GIORGIO
BOSCAGLI He prefers a big steak and not coffee. Luckily, Sandrino
and Lorretta turn out to be a good match - at least genetically.
While all the Abruzzo bears are related, at least these two
are distant cousins. And the hope is that someday their offspring
will help boost the wild Abruzzo population. Loretta, meanwhile,
seemed to be getting bored with honey.

ALAN ALDA Now she wants to eat something else and that's starting
to bother me. What do you like? You don't like hamburger or
anything? Does she eat actors?

FRANCO
TASSI Hmmm?

ALAN ALDA Mange actori?

FRANCO
TASSI Mange actori?

ALAN ALDA Yeah.

FRANCO
TASSI A mangato.

ALAN ALDA Oh, oh yeah? She ate one already! Oh good.

ALAN ALDA (NARRATION) Right next door to the bears is a pen of
Abruzzo chamoix - rare alpine goats. They offer both encouragement
and a warning to the effort to save the bears.

ALAN ALDA How many these chamoix do you have now?

FRANCO
TASSI Now in the Abruzzo National Park we have more than 600
Abruzzo chamois. But when the park was created in 1922 there
were only 30 left.

ALAN ALDA So you went from 30 to 600 in those years.

FRANCO
TASSI Yes, this was a big success. And we plan to reintroduce
the chamois in other big Abruzzo mountains.

ALAN ALDA (NARRATION) There may be 600 chamoix here in the park,
but they have a potentially fatal weakness - which this expedition
of wildlife biologists is now hoping to fix. The weakness
is exactly the one worrying those trying to bring back the
Abruzzo bears - all 600 animals are dangerously inbred.

FRANCO
MAURI The problem with this population is it's the last population
of this kind of chamois and for a long time there was a small
number of animals. So all the animals are like brother and
sister, so the genetic variability is very low.

ALAN ALDA (NARRATION) The big risk when all the animals are close
relatives is that a disease could wipe them all out. This
chamois round-up aims to reduce this risk by taking some of
the herd to new homes. But the round-up itself isn't without
risk. Tranquilized chamoix overheat from the stress. Ice packs
keep them cool for a while, but now they must be gotten to
their new homes as quickly as possible. This trip is to a
newly established national park, 50 miles away. Here they'll
be isolated from the original herd, so a disease can't sweep
through the whole population. One animal - an older female
- is overheating, and the veterinarians are growing anxious
for her safety. A shot of adrenaline wakes up the first animal,
who's wearing a radio collar so she can be tracked in her
new home. But the older female is in trouble. She wakes up,
but doesn't have the strength to run.

LEONARDO
(IN ITALIAN) She's very stressed. The whole process has stressed
her system. Her reaction is panic and an inability to run.

ALAN ALDA (NARRATION) They try helping her to her feet - to no
avail. It's a heartbreaking loss for the biologists, whose
attempt to ensure the species' survival has cost this chamois
her life. But she's only the third animal to be lost out of
150 airlifted in the last four years... and the other chamoix
on this trip are all fine. Safe here on an Abruzzi mountain
that hasn't seen a chamois in living memory, these animals
will, with luck, establish a new herd that will call this
mountain home. From the wilds of the Abruzzo, we traveled
to the eternal city, Rome. Much less well known than its monuments
and statues are Italy's contributions to medicine. It was
in Italy that the science of anatomy began in the 1500s -
opening the way, eventually, to surgery.

LONG
DISTANCE DOC

ALAN ALDA This is the Policlinico Umberto Primo, where they've
been performing and teaching surgery for almost a century
now. But up there on the top floor they're pioneering a new
form of surgery which may take us into the next century. This
is how you normally see doctors washing up before an operation.
But today Dr. Angelini and I don't have to be too careful
about how clean we are because we're very unlikely to infect
the patient, who is about 360 miles, away in Milan.

ALAN ALDA (NARRATION) And there's another reason we didn't have
to scrub too carefully. Our patient in Milan is an assembly
of plastic parts - which, as it turned out, was just as well.
The liver is the organ we were to operate on. The cyst we
were after is a fluid-filled balloon, and the skin is latex.
The Rome-Milan research team is one of several in the world
working on long distance remote-control surgery - the idea
being that one day surgeons could operate on battlefields
or in space without leaving the office. In today's experiment,
video of the operation is transmitted to Dr. Angelini's office
in Rome.

LICINIO
ANGELINI We start the system.

ALAN ALDA (NARRATION) At least, that was the plan. When the satellite
link went down, we were left with the phone line - and still
images only.

ALAN ALDA Ahhh, buon giorno!

LICINIO
ANGELINI Ah, Professor Rovetta.

PROFESSOR
ROVETTA Good morning, how are you?

LICINIO
ANGELINI Now we see you. Are you ready to start the procedure
for the biopsy?

PROFESSOR
ROVETTA Start now, okay.

LICINIO
ANGELINI I have selected the first spot for the incision.
I am confirming now.

ALAN ALDA How do you know where you want to put the first incision?

LICINIO
ANGELINI Because that's my job.

ALAN ALDA But I mean all you see if this square of skin.

LICINIO
ANGELINI Yes but we know how the field is selected. So this
would be the ribs and I know that the first cut should be
there.

ALAN ALDA Okay.

ALAN ALDA (NARRATION) At the click of the mouse, the robot arm
plunges the scalpel into the selected spot.

LICINIO
ANGELINI I ask Dr. Alda to make the cut.

ALBERTO
ROVETTA Wonderful. He becomes a surgeon today.

ALAN ALDA (NARRATION) You'll understand, I was having a little
trouble taking this seriously.

ALAN ALDA This will only hurt for a second. I cut.

ALBERTO
ROVETTA Once more please.

ALAN ALDA There. I cut again.

ALBERTO
ROVETTA Yes. That's enough now. The cut is very long.

ALAN ALDA Well, let's delete some of those cuts.

ALAN ALDA (NARRATION) The scalpel is switched for the biopsy needle.
By this time, the patient is already a little the worse for
wear. So that we surgeons in Rome can find the cyst, the Milan
team employs an ultrasound probe.

LICINIO
ANGELINI Can we get the image of the cyst from the ultrasound
screen?

PHONE VOICE Yes, in a few seconds.

LICINIO
ANGELINI Great.

ALAN ALDA Oh, okay, this is an ultrasound.

ALAN ALDA (NARRATION) The image shows us inside the body.

LICINIO
ANGELINI You see, this is the cyst. This black hole is the
cyst in the liver. This is all liver.

ALAN ALDA So if you're operating remotely like this and you're
looking at what you're doing on this ultrasound picture. Is
that more accurate than if you were there in the room or less
accurate?

LICINIO
ANGELINI At least as accurate as by hand but probably more
accurate, because there is no way to make a mistake. You can
calculate exactly the depth where you want that the needle.
And that will be inside this black area which is the cyst.
We can be sure that the needle goes there.

ALAN ALDA (NARRATION) But Dr. Angelini's optimism proved a bit
premature. The needle goes in to the selected depth ...

LICINIO
ANGELINI And now we pump.

ALAN ALDA (NARRATION) ... but when he tries to pump the fluid out,
nothing happens.

DOCTOR
IN MILAN The position is not correct. You were in the right
position but then the needle moved. So you should repeat once
again the puncture.

ALAN ALDA (NARRATION) The patient has to endure a second puncture.
But still, no fluid.

LICINIO
ANGELINI I pushed the pump again. Is it sucking?

ALAN ALDA (NARRATION) Now here's an intervention you couldn't do
in real life -- open the abdomen and reposition the cyst.
Finally, on the third try, Dr. Angelini hits the cyst, and
pumps out the fluid. Mercifully, the operation is over. Now,
I should point out that in other tests - including a satellite
link up between California and Milan - the operation went
much more smoothly. This clearly wasn't Dr. Angelini and Dr.
Rovetta's day - or, if it comes to that, Dr. Alda's either..

ALAN ALDA How did we do today with this patient. Did this patient
survive? Is the patient happy?

ALBERTO
ROVETTA Everything is okay, because the cuts can be repeated.
And I think the patient will be very happy for his health.

ALAN ALDA (NARRATION) Tele-robotic surgery is clearly an idea whose
time will come - one day.

LICINIO
ANGELINI Frankly speaking, if I were the patient today, I
wouldn't be very happy.

ALAN ALDA (NARRATION) Early morning in Pozzouli, on the Bay of
Naples - and the fish market is open for business. I'm here
with biologist Graziano Fiorito. He comes to market not to
buy his dinner but to find subjects for his lab.

ALAN ALDA What about these guys?

GRAZIANO
FIORITO These are good enough.

ALAN ALDA (NARRATION) This is the animal Fiorito works with --
the octopus, one of the least-loved creatures of the sea.
At first it's hard to figure out just how the octopus is put
together.

ALAN ALDA Where are his eyes?

GRAZIANO
FIORITO The head is this. This is eyes.

ALAN ALDA And what's this? It looks like a big nose.

GRAZIANO
FIORITO This is the abdomen of the animal.

ALAN ALDA Oh, the abdomen. It's not his nose. And where's his mouth?

GRAZIANO
FIORITO The mouth is underneath.

ALAN ALDA In the middle of his hands.

GRAZIANO
FIORITO Yes, here, you see it.

ALAN ALDA (NARRATION) Graziano Fiorito takes his subjects back
to the zoological station in Naples, Europe's oldest marine
biology laboratory. As an invertebrate, the octopus may be
spineless but it is a skilled hunter. Lurking behind a rock,
this one is stalking a hermit crab. Octopuses live alone,
so it's thought that their hunting skills are partly pre-programmed
in their genes and partly self-taught from experience. The
idea that a creature as lowly as an octopus might also learn
as we do, by watching others, would be heresy to most scientists.
But that's just what Fiorito believes he's seen. Here's the
challenge he sets for the octopuses he buys from the market
- a glass jar containing a crab, and sealed tightly with a
plug. Some octopuses, perhaps because they've opened a lot
of shells for their dinner, open the jar on their first try.
Others, like this one, can be given the jar time and time
again without getting inside. I joined Fiorito for the key
experiment. The octopus on the right is the one that can open
the jar. The one on the left can't.

ALAN ALDA You already gave him a jar and he couldn't do it?

GRAZIANO
FIORITO No. Half the population of animals that come from
the sea are able to do it and the other half they are unable
to do it. So it depends let's say from the individual's experience.
There are some octopus that are more skilled than other ones.

ALAN ALDA (NARRATION) The unskilled animal will be given a chance
to watch how it's done.

ALAN ALDA So now the octopus over here in this tank is going to
watch this one open the jar.

GRAZIANO
FIORITO That's right.

ALAN ALDA (NARRATION) Even knowing how to do it didn't help me.

ALAN ALDA I need suction cups on my fingers here. I can't do it.

ALAN ALDA Does he see it yet do you think?

GRAZIANO
FIORITO Yes.

ALAN ALDA (NARRATION) The skilled octopus sees the crab immediately
and moves in. The unskilled octopus seems to be watching intently,
as the skilled one explores the jar.

GRAZIANO
FIORITO It's crawling now on the jar and it recognizes the
plug. Now its behavior is changed - now it's carrying it right
back home to be more safe from the other animal.

ALAN ALDA He doesn't want the other animal to interfere?

GRAZIANO
FIORITO That's right.

ALAN ALDA (NARRATION) The performer pulls the plug and the crab
is his. Meanwhile, the observer octopus is scrambling for
the best view.

ALAN ALDA Do you think that this animal from observing that this
time may know how to do it?

GRAZIANO
FIORITO We can try.

ALAN ALDA Great, can we see?

ALAN ALDA (NARRATION) Now remember, this animal has never before
been able to open the jar. What's new is that he's observed
the solution.

ALAN ALDA Oh here he goes, here he goes. Look, look, look, look.
Oh wow, look at him. Just went right at it.

ALAN ALDA Look, he got in, he got it open. And he was never able
to do that before?

GRAZIANO
FIORITO No.

ALAN ALDA This is unbelievable.

ALAN ALDA (NARRATION) What Graziano Fiorito's has shown for the
first time is that an invertebrate can learn by observing.
Social learning like this is a domain of intellect usually
reserved for mammals like us. But as I learned in the fish
market, you have to you know how to handle an octopus if you
want it to show you its secrets.

ALAN ALDA Why do you need to be relaxed with an octopus?

GRAZIANO
FIORITO If you would like to study behavior of animals the
animal must be sure that you would never kill him. There is
such a kind of, let's say, good relationship between you and
the animal, a good feeling.

ALAN ALDA You have to have a sure touch, huh? Well I don't have
it. I think these animals can sense it.

ALAN ALDA (NARRATION) Looming over the Bay of Naples is Mount Vesuvius,
a volcano that caused one of history's most famous disasters.
Nearly two thousand years ago, the Roman city of Pompeii was
destroyed when Vesuvius erupted. The city and two thousand
people disappeared under a wave of volcanic rock and hot poisonous
gas. Seventeen centuries went by before Pompeii was re-discovered
... under twenty feet of ash and rock -- a city frozen in
time. Today, the site is a popular spot for tourists. Among
the sights - the world's oldest "Beware of Dog" sign.

ALAN ALDA How old was Pompeii before ...

GIUSEPPE
LANZIANO More or less 700 years.

ALAN ALDA Before it got destroyed?

ALAN ALDA (NARRATION) My guide to this Italian ghost town was Giuseppe
Lanziano.

ALAN ALDA What are these?

GIUSEPPE
LANZIANO Okay. You have here the special tracks of the chariots
left here by the wheels, very deep in some places.

ALAN ALDA They'd come through here and make these marks through
the stone?

GIUSEPPE
LANZIANO Yes, through the stone.

ALAN ALDA So I can see that 700 years of chariots would make those
marks.

ALAN ALDA (NARRATION) Archaeologists just uncovered this tragic
scene -- victims caught inside their house. Suffocated by
gas and ash, they were cast in volcanic rock where they fell.

GIUSEPPE
LANZIANO Here we can see the family, complete family. Piece
of wood.

ALAN ALDA That wood came down from the roof?

GIUSEPPE
LANZIANO Fell down from the roof. And a pregnant woman, six
months pregnant here, the lady. Husband here.

ALAN ALDA It looks like he's trying to shield her.

ALAN ALDA (NARRATION) This family was obviously taken completely
by surprise - even though they knew they lived next to a volcano.

ALAN ALDA They knew it could go ...

GIUSEPPE
LANZIANO Could go, yes.

ALAN ALDA And yet they carried on their normal lives. They lived
right here at the base of the mountain. Where do you live?

GIUSEPPE
LANZIANO Actually now in New Pompeii.

ALAN ALDA Where's that?

GIUSEPPE
LANZIANO Just there, half a mile far from here. But we are
not afraid.

ALAN ALDA (NARRATION) Giuseppe's confidence - and that of other
Neapolitans - lies in the belief that there will be plenty
of warning before another eruption. The person whose responsibility
that warning would be is Lucia Civetta, who directs a team
that continuously monitors the volcano. She was willing to
sit beside the crater, so... PROFESSOR CIVETTA This is the
crater of the last eruption of Vesuvius, the 1944 eruption
of Vesuvius. This crater was formed during that eruption.
Before 1944 you can walk from this side to the other side.

ALAN ALDA So what happened to all the stuff that was there, between
here and there, that went up? PROFESSOR CIVETTA Ya, ya.

ALAN ALDA That's what I thought.

ALAN ALDA (NARRATION) Vesuvius's eruptions have a pattern. The
1944 eruption counts as a small one, happening about once
a century. Pompeii-sized eruptions happen every 2000 years
or so - and Pompeii was destroyed just over 1900 years ago.
Which means the stakes get higher every year for Lucia Civetta
and her Vesuvius monitoring teams. Every week, researchers
climb down into the crater to take the volcano's pulse. These
steaming fumeroles are venting from deep within the volcano.
The gases provide clues to what's brewing in the chamber of
molten magma that sits three miles beneath the summit. Today's
measurements are reassuring. Both the radon gas levels and
temperature are stable. But while the volcano sleeps, the
population on its flanks is exploding. Two million people
now live within a few miles of Vesuvius. And if they believe
the science of prediction will save them - they need look
only 300 miles to the south. In Sicily, in December 1991,
Mount Etna erupted. Scientists monitoring the volcano knew
for months activity was building - but no-one predicted what
would prove to be the real danger - an eruption a mile below
the main crater on the mountain's flank. The unknown now was
where this river of molten lava would lead. In an attempt
to find out, scientists turned to a new predictive tool -
computer simulation. On a three-dimensional computer model
of Mt. Etna, researchers sited the vent and an estimate of
how much lava was flowing. The model simulated the possible
routes the lava could take. The most likely, shown in red,
was channeled through a narrow pass right above the town of
Zaffarena. If the eruption was a long one, the model predicted
the town's total destruction. Taking the prediction seriously,
officials hastily built an immense earth dam across the pass
- a barrier 60 ft high and a half-mile long. Meanwhile, the
lava crept down the mountain - following exactly the course
the simulation had predicted. The barrier held back the lava
for a month. Then in April 1992, it crested the barrier. But
the prediction had brought time for the authorities to plan
their next move. In an extraordinary effort, helicopters from
the US Navy joined the battle in an attempt to directly plug
the lava vent. But even American dumpsters couldn't stop the
flow. In Zaffarena, nerves were fraying. With the lava now
just half a mile from town, residents awaited orders to evacuate
- and dug last ditch defenses. But then the computer simulation
suggested a dramatic new strategy. The model suggested that
high explosives could divert the flow into an artificial channel
dug to the left of its original course. The strategy worked.
The lava emptied into an unpopulated valley. And the original
lava flow stopped three hundred yards from Zaffarena. In Sicily,
a computer model had helped save a town. Back on Vesuvius,
I met up with Flavio Dobran, who hopes his computer simulation
might prevent a modern-day Pompeii. Vesuvius isn't like Etna.
A large scale eruption here would produce not slow moving
lava but a 200 mile an hour avalanche of super-heated gas
and rock.

ALAN ALDA 200 miles per hour? There's no hope of ever getting out
of the way.

FLAVIO
DOBRAN 200 miles an hour at a temperature of about 2000 degrees
Fahrenheit. And to give you an idea it takes about five minutes
for these flows to reach from here all the way down to the
sea. Five minutes. In about three minutes you're already to
the autostrada, which passes about seven kilometers down there.

ALAN ALDA And that's the way out.

FLAVIO
DOBRAN No, that's not the way out. That's panic.

ALAN ALDA (NARRATION) When Flavio's results were published, they
caused a political uproar in the area. Here was a detailed
scientific model predicting a modern-day Pompeii in the making.
The only evacuation route, the autostrada, will be wiped out
in three minutes, trapping 700,000 people. Flavio Dobran believes
the only practical strategy is to somehow block the path of
the flow before the eruption occurs.

ALAN ALDA Now you would like to see barriers built?

FLAVIO
DOBRAN Not necessarily barriers. A barrier can be just a part
of a condominium.

ALAN ALDA So you could live in an apartment-dash-barrier.

FLAVIO
DOBRAN That's right. One part of the building could just be
a barrier, which you don't see. So you could build ... speaking
freely ... you could build a set of houses down there, which
one part looking toward the volcano is really a barrier.

ALAN ALDA Do you think that these people would get a little break
on the rent?

FLAVIO
DOBRAN Actually no, because the closer you come to here the
more it would cost because you get a more beautiful view.

ALAN ALDA For a while anyway.

ALAN ALDA (NARRATION) To test this idea, Flavio built 90-ft high
barriers in his computer model. The first is quickly over-run.
But the second, 3 miles below the summit, shields the autostrada.

FLAVIO
DOBRAN We ran the simulations up to 1000 seconds and the barrier
was holding the flow.

ALAN ALDA So not only would many lives have been saved if that
held true in reality, but the escape route would also have
been preserved.

FLAVIO
DOBRAN Well, you would save several hundred thousand people.

ALAN ALDA (NARRATION) So for those who choose to live with volcanoes,
simulated eruptions may help them survive the real thing.
Still, there are easier ways.

ALAN ALDA (NARRATION) Between Rome and Italy's east coast the autostrada
cuts through the mountainous spine of Italy - the Apennines.
The highest peak is called the Gran Sasso.

ALAN ALDA Most people come to the mountains for the breathtaking
views. But for some people the most breathtaking sights aren't
on top of the mountain - they're underneath it. This tunnel
runs for about five miles underneath the Gran Sasso mountain.
There's supposed to be a turn off here somewhere....

ALAN ALDA (NARRATION) What we're looking for turned out to be one
of the most amazing - and certainly most unexpected - of all
the places we visited in Italy, a laboratory cut into the
heart of the mountain.

ALAN ALDA Hello. Alan Alda, Scientific American Frontiers.

ALAN ALDA (NARRATION) It's hard to believe it from here, but the
laboratory beyond these doors is trying to solve perhaps the
biggest puzzle in the universe - where, and what, most of
the universe is. The lab looks like the set for a science
fiction movie. This giant yellow box, 40 ft high and almost
a football field long, is actually one of the world's biggest
scientific instruments. My guide to the lab is its scientific
director, Doug Michael. What he's using the instrument to
look for is the 90% of the universe no one can find.

DOUG
MICHAEL .....We know that the galaxy needs more matter to
clump it together. There's just not enough matter....

ALAN ALDA (NARRATION) The detector is trying to find what's literally
lost in space.

ALAN ALDA Is this place that we're in, in a way a telescope?

DOUG
MICHAEL Yeah. Only it's under a mountain. So it's really a
telescope under a mountain.

ALAN ALDA (NARRATION) When we look into space with conventional
telescopes the galaxies we see are unimaginably large clusters
of stars. But the visible stuff in galaxies is only about
10% of what's needed to provide enough gravity to hold them
together. Something out there is providing the cosmic glue
- but what? One idea about what this invisible missing matter
might be suggests that a lot of it is flying though us all
the time. The earth is being constantly bombarded by invisible
particles from outer space - cosmic rays. Most of them can't
get through a lump of rock as big as the Gran Sasso. But a
few do - and they're the ones that are candidates for what's
missing in the universe. Down here they can be spotted because
they create other particles called muons.

DOUG
MICHAEL A muon is essentially a high energy moving-at-the-speed-of-light
particle, and it just comes flying right through the detector
right? There goes one right now - they come through every
few seconds.

ALAN ALDA That's amazing, I missed it, it goes so fast.

DOUG
MICHAEL It just came right through. Anyway our electronics
are capable of recording that muon when it comes in, because
we have detector planes..

ALAN ALDA (NARRATION) The detector has been put down here under
5000 ft of solid limestone precisely because the rock shields
it from most cosmic rays - allowing through only the ones
that Doug Michael and his colleagues think are interesting.

DOUG
MICHAEL It's sort of like if you had a flute playing in a
thousand piece brass band or something like that. You would
never hear the flute.

ALAN ALDA So in a way this is creating a quiet room.

DOUG
MICHAEL It's a quiet environment that allows us to be able
to see these really rare events.

ALAN ALDA (NARRATION) The rare event he'd most like to see is the
track left by what has to be one of the strangest things I'd
ever heard of - something called a magnetic monopole.

DOUG
MICHAEL Any magnet we've ever built on earth always has two
poles to it, a north pole and a south pole, OK? What a magnetic
monopole would be is as if you could just separate out one
of those poles from the other. You can try it with a magnet
if you like - you can chop a magnet up into as many pieces
as you like and you'll never succeed.

ALAN ALDA You'll always have a piece that has north on one side
and south on the other. So how could you possibly have a monopole
that's only north or south?

DOUG
MICHAEL Ah. First of all, there's no reason that you can't
have it . It's just- that we don't seem ever to have found
such a thing.

ALAN ALDA (NARRATION) The reason for looking for magnetic monopolies
is that they are prime candidates for being some of that missing
matter in the universe. They may be so small as to be invisible
except to an underground telescope like this - but they have
one thing going for them if you're looking for missing mass.

DOUG
MICHAEL They're so massive that they could have only been
produced in the very earliest, earliest moments of the Big
Bang.

ALAN ALDA So, they're not being produced now in stars or supernova
or anything.

DOUG
MICHAEL Absolutely, there's no process in the whole universe
that could produce a magnetic monopole.

ALAN ALDA Only the big Bang was powerful enough. So from that time,
that event, that Big Bang, they're still out there somewhere...here
somewhere.

DOUG
MICHAEL We think they have to be there. The problem is we
have no idea of how many of them there have to be. There could
be anywhere from millions of them floating around us all the
time, to one in the whole universe!

ALAN ALDA (NARRATION) So far, in the year the detector's been looking,
no monopoles have turned up - not surprising if there's only
one in the universe! But the search continues. Because if
magnetic monopoles exist, they could be the missing cosmic
glue that sticks the whole universe together.

ALAN ALDA This is the city of the Renaissance, Florence. Here,
for 200 years starting in 1400, art and architecture were
reborn. It all began right down there in the heart of the
city, in the Piazza del Duomo.

ALAN ALDA (NARRATION) In the late 1300s, Florence was experiencing
a building boom. A brand new cathedral was almost finished,
and the old baptistery was being renovated. New doors for
the baptistery were planned, and a competition to design them
was won by a sculptor named Lorenzo Ghiberti. The striking
perspective and realism of the bronze panels are often taken
to mark the beginning of the Renaissance. The big loser in
the door contest was Ghiberti's arch-rival, Filippo Brunelleschi.

ALAN ALDA Ghiberti may have beaten out Brunelleschi for the design
of the Baptistery doors, but Brunelleschi managed to get his
revenge - and in doing so he achieved the greatest feat of
engineering of his age.

ALAN ALDA (NARRATION) The building of the cathedral was going well
- except for one big problem. No-one could figure out how
to build the immense dome that now dominates the Florence
skyline. There the cathedral sat in 1418, work at a halt,
domeless.

ALAN ALDA Brunelleschi and Ghiberti were jointly appointed master
architects of the dome. But there was one big difference between
them. Brunelleschi had a plan and Ghiberti didn't. Brunelleschi
wanted the job all to himself, so he called in sick. He pretended
to be ill which left the job to Ghiberti, who before long
was completely lost. Then miraculously Brunelleschi recovered
and returned to the job. Here's the problem he faced. The
area that had to be covered by the dome was 180 feet wide
and 180 feet high. In those days the way you made a dome was
you filled the entire space with scaffolding. In fact they
just restored the dome and that's how they did it. They're
just removing the last of the scaffolding now. But in Brunelleschi's
time wood was extremely expensive. The city fathers couldn't
afford all that scaffolding. Brunelleschi's plan didn't need
it. Instead, he invented some unique machines, machines so
secret that he made sure nobody ever saw the designs.

ALAN ALDA (NARRATION) Luckily, sketches of Brunelleschi's machines
were made later by - of all people - the grandson of his losing
rival. They reveal a grasp of mechanics usually associated
with Leonardo da Vinci, who worked 50 years later. Brunelleschi
invented hoists, cranes and machines to position the stones
in the dome, as well as a unique design for the dome itself,
consisting of an inner and outer shell. One of his cleverest
machines was the huge hoist that hauled the stones 180 ft
up to the masons working in the dome above. Recently, this
machine has been given a new - electronic - life. A short
walk across Florence from the cathedral is a museum most of
the city's tourists overlook - the Museum of the History of
Science. The museum is involved in an ambitious plan to recreate
in the computer working models of Brunelleschi's machines.
Here's the hoist. And in the computer reconstruction you can
see what made it so clever - it's reversible.

ALAN ALDA Let me see. When it's up it goes in this direction. When
it's down it goes in the other direction, like that. And the
horse goes in one direction only.

ALAN ALDA (NARRATION) Without this reversible gear, the horse would
have had to be unharnessed and turned around between loads.
It was the first time anyone had built such a machine.

ALAN ALDA (ITALIAN) It was the first time.

MARCO
BERNI (ITALIAN) That they had something like this, yes. Brunelleschi
wasn't the only 15th century Italian designing machines -
though most of them stayed on the drawing board. This human-powered
pile driver by Francesco di Giorgio has also been now built
in the computer, and is today driving piles for the first
time. This water powered saw designed by an engineer named
Taccola also seems to work just fine. Di Giorgio designed
a water pump. He also went in for high- tech weapons, like
this missile launcher. A mechanical ladder for scaling walls.
Even a nasty device for stopping enemy ships. Machines like
these - even if only imagined - were very much a part of the
spirit of innovation that characterized the Renaissance. Thanks
to Brunelleschi's machines, the citizens of Florence saw his
magnificent dome slowly materialized between 1420 and 1470
- and Florence's crown jewel was complete.

ALAN ALDA (ITALIAN) That's all for this edition of Scientific American
Frontiers. Goodbye - see you soon.